Mounting system for parallel straight edge



July 1967 V. N. BARZEE ET MOUNTING SYSTEM FOR PARALLEL STRAIGHT EDGE Filed NOV. 15, 1965 I 2 Sheets-Sheet 1 FIE-l V52; A/. 54225: M05524 d 664mm 7 July 4, 1967 v BAR EE ET AL 3,328,886

MOUNTING SYSTEM FOR PARALLEL STRAIGHT EDGE Filed Nov. 15, 1965 2 Sheets-Sheet 2 VEEL A! 542255 f I E. 4. dos/s y (/HAPAPA r INVENTORS United States Patent 3,323,886 MOUNTING SYSTEM FOR PARALLEL STRAIGHT EDGE Verl N. Barzee, 708 Knickerbocker Drive 94087, and

Joseph J. Harapat, 1105 W. Iowa Ave. 94086, both of Sunnyvale, Calif.

Filed Nov. 15, 1965, Ser. No. 507,887 3 Claims. (Cl. 3380) The present invention relates to drafting apparatus and particularly to the system for mounting a parallel straight edge on a drafting board.

An object of the present invention is to provide a new and improved apparatus for mounting a parallel straight edge.

Another object is to provide an apparatus for independently adjusting the alignment and drag of a straight edge.

Still another object is to provide an apparatus for independently adjusting the drag force on each end of the straight edge.

A further object is to provide an apparatus for quickly an easily aligning a parallel straight edge which may be manufactured inexpensively from rugged parts which will give long lasting service.

A still further object is to provide a system for a parallel straight edge which may be adapted to all standard drafting tables.

Still another object is to provide an apparatus which will permit the straight edge to be removed easily and quickly for cleaning and which may be re-connected to the board without changing the pre-set alignment and drag of the straight edge.

The invention possesses other objects and features of advantage, some of which of the foregoing will be set forth in the following description of the preferred form of the invention which is illustrated in the drawings accompanying and forming part of this specification. It is to be understood, however, that variations in the showing made by the said drawings and description may be adopted within the scope of the invention as set form in the claims With reference to said drawings (two sheets) FIGURE 1 is a plan view of the apparatus constructed in accordance with the present invention.

FIGURE 2 is an enlarged fragmentary cross-section of a portion of the aparatus taken substantially along the line 2-2 of FIGURE 1.

FIGURE 3 is an enlarged side view of a portion of the device with portions broken away for purposes of clarity and taken substantially along the line 33 of FIGURE 1.

FIGURE 4 is a bottom device shown in FIGURE 2 the line 4-4.

The parallel straight edge mounting apparatus of the present invention consists briefly of a drafting table 6 having a planar surface 7; a straight edge 8 mounted for reciprocating movement over the surface; a pair of flexible substantially non-elongated members 11 and 12 operatively connected to the straight edge and each having first ends 13 and 14 and second ends 16 and 17 respectively aflixed to the table providing parallel reciprocating movement of said straight edge and first means 19 and 20 independently biasing respectively each of the first ends of the members to the table.

Tnere are several ways of mounting a parallel straight edge and for purposes of describing this invention one of the common ways is shown in FIGURE 1. End 24 of the straight edge is provided with sheave 25 mounted for free rotation thereon and for receiving the flexible memview of the portion of the and taken substantially along for parallel straight edges and are her 11. Sheave 26 is mounted on end 24 of the straight edge for free rotation thereon and is positioned for engagement with flexible member 12. The other end 28 of the straight edge is provided with sheave 29 mounted thereon for free rotation and in engagement with flexible member 12. Sheave 30 is mounted for free rotation on end 28 of the straight edge and engages flexible member 11.

Each of the biasing means 19 and 20 include a manually engageable member 32 and 33 respectively for adjusting the biasing force on each of tne flexible members 11 and 12. The biasing means 19 may be more clearly seen in FIGURE 2 and consists briefly of a housing 36 having a threaded bore 37 opening to one end 38, the manually engageable member 32 being formed with threads 39 for threadable receipt in the bore and being formed with an internal bore 41 therethrough, a piston member 42 formed and dimensioned for sliding receipt in the internal bore, formed with a spring retainer 43 and adapted for receiving an end 13 of the flexible member and a spring 47 mounted between the spring retainer and the manualy engageable member at face 48 for adjustable biasing of the flexible members. Flexible member 11 may be attached to the piston member in several ways and as here shown the piston member is formed with an internal bore 51 through which the string is threaded and the end 13 is provided with an enlarged end or knot 52 which bears against spring retainer 43.

A second means 56 and 57 is connected respectively to the second end of the flexible member one of which is shown in greater detail in FIGURE 3. Each of the second means have a manually engageable member 58 and 59 respectively for independently adjusting the eifective length of each of the flexible members for adjusting the alignment of the straight edge.

The second means is shown in greater detail in FIG- URE 3 and each includes a housing 62 having a threaded bore 63 therein opening to one end 64, the manually engageable member being formed with threads 66 dimensioned for threadable receipt in the bore and being adapted for holding a second end 16 of the flexible member 11. The manually engageable member is formed with a bore 71 for receiving the end 16 of the string which in turn is connected by an enlarged head or knot 72 in engagement with end 73 of the manually engageable member.

It is essential that every parallel straight edge be removable from the drafting board for purposes of cleaning the board and the under edge of the straight edge. We have found that spring biasing both flexible members makes it possible to quickly and easily remove the straight edge and all of the apparatus above described from the board. A fastener 74 having a head 76 is attached to the board. Each of the housings is formed with a key slot opening 78 for receiving the shank 79 of the fastener 74.

Flexible members 11 and 12 are standard equipment preferably stainless steel woven cable having an outside diameter of about 40-45 one-thousandths inch.

The two springs for the apparatus are identical and the spring force depends upon the use and size of the drafting board. A standard board will require a spring having a diameter of about inch and about 6 to 8 convolutions. The spring length is approximately one-half inch.

In order to adjust the alignment of the straight edge it is merely necessary to adjust either manually engageable member 58 or 59. Tightening manually engageable member 59 so as to effectively shorten the length of flexible member 11 causes the straight edge to pivot in a clockwise direction as shown in FIGURE 1 about a pivot point formed by end 24. 'In effect, the straight edge forms a moment arm the length of the straight edge and thus tightening of the member 59 causes the spring in the first means to compress and movement of end 28 of the straight edge to the right as shown in FIGURE 1. Turning of the manually engageable member 59 so as to effectively lengthen flexible member 11 causes the end 28 of the straight edge to move to the left as shown in FIG- URE 1 and the spring in first means 20 is uncompressed. Thus simply rotating manually engageable member 59 moves end 28 of the straight edge thus permitting alignment of the straight edge.

In like manner, end 24 of the straight edge may be moved to the left or right as shown in FIGURE 1 by merely turning manually engageable member 58.

After rotating either manually engageable member 58 or 59, the springs in first means 19 or 20 will be unequally compressed thus causing greater tension on one of the flexible members 11 or 12. Spring tension may be equalized by rotating either manually engageable member 32 or 33.

The ability to change the spring tension on both flexible members is important to the smooth running operation of the straight edge. An increase in tension on one spring increases the bearing friction of the sheaves and causes one side of the straight edge to have a greater drag than the other side. Another reason to be able to adjust the spring tension is to increase the drag where the board is tilted at an angle so that the straight edge will not fall to the bottom of the board. When the board is nearly horizontal, a decrease in the spring tension will permit an easier running straight edge.

A still further advantage of the use of spring biasing in both flexible members is the ability to skew the straight edge both clockwise and counter-clockwise in order to draw lines slightly out of parallel with the aligned straight edge.

Thus in order to skew the straight edge in a clockwise direction as shown in FIGURE 1 it is merely necessary to apply pressure to the right against end 28 thus compressing the spring in means 20. In like manner to skew the straight edge in a counter-clockwise direction it is merely necessary to apply force in a direction to the right against end 24 of the straight edge thereby compressing spring 47.

To remove the straight edge from the board the only operation necessary is to successively pull the housings of means 19, 20, 56 and 57 away from the straight edge so as to move the shank of the fastener into the widened part of the keyhole slot and then pull upwardly. Thus in moving the housing of means 56, the spring of means 20 would be compressed. In like manner, moving the housing 62 would compress spring 47.

We claim:

1. A parallel straight edge mounting apparatus comprising; .a drafting table having a planar surface: a straight edge mounted for reciprocating movement over said surface; a pair of flexible substantially non-elongatable members operatively connected to said straight edge and each having first and second ends affixed to said table providing parallel reciprocating movement of said straight edge; first means independently biasing each of the first ends of said members to said table and having a hand engageable member for variably adjusting the biasing force on each of the first ends of said members; and second means connecting the second ends of said flexible members to said table and having manually engageable members for independently adjusting the effective length of each of said flexible members for adjusting the alignment of said straight edge wherein:

each of said biasing means includes a housing having a threaded bore therein opening to one end, said manually engageable member being formed and dimensioned for theradable receipt in said bore and being formed with an internal bore therethrough, a piston member formed and dimensioned for sliding receipt in said internal bore, formed with a spring retainer and adapted for receiving an end of said flexible member and a spring mounted between said spring retainer and said manually engageable member for adjustable biasing of said flexible members.

2. A parallel straight edge mounting apparatus comprising:

a drafting table having a planar surface;

a straight edge mounted for reciprocating movement over said surface;

a pair of flexible substantially non-elongatable members operatively connected to said straight edge and each having first and second ends aflixed to said table providing parallel reciprocating movement of said straight edge;

first means independently biasing each of the first ends of said members to said table and having a hand engageable member for variably adjusting the biasing force on each of the first ends of said members;

second means connecting the second ends of said flexible members to said table and having manually engageable members for independently adjusting the effective length of each of said flexible members for adjusting the alignment of said straight edge;

said table including a pair of studs mounted thereon;

and

said first means each include a spring for biasing said members and for holding said first means in engagement with said studs and which are adapted for removable connection to said table by externally overcoming the biasing force of said springs.

3. An apparatus as described in claim 2 comprising:

said studs each having an enlarged head; and

said first means having a housing formed with a key hole slot dimensioned for releasable connection to said studs.

References Cited UNITED STATES PATENTS 714,594 11/1902 Marx 3380 2,824,717 2/ 1958 Yeager 24-68 X FOREIGN PATENTS 35,485 8/ 1929 France. 1,344,431 10/ 1963 France.

LEONARD FORMAN, Primary Examiner.

H. N. HAROIAN, Examiner. 

1. A PARALLEL STRAIGHT EDGE MOUNTING APPARATUS COMPRISING; A DRAFTING TABLE HAVING A PLANAR SURFACE; A STRAIGHT EDGE MOUNTED FOR RECIPROCATING MOVEMENT OVER SAID SURFACE; A PAIR OF FLEXIBLE SUBSTANTIALLY NON-ELONGATABLE MEMBERS OPERATIVELY CONNECTED TO SAID STRAIGHT EDGE AND EACH HAVING FIRST AND SECOND ENDS AFFIXED TO SAID TABLE PROVIDING PARALLEL RECIPROCATING MOVEMENT OF SAID STRAIGHT EDGE; FIRST MEANS INDEPENDENTLY BIASING EACH OF THE FIRST ENDS OF SAID MEMBERS TO SAID TABLE AND HAVING A HAND ENGAGEABLE MEMBER FOR VARIABLY ADJUSTING THE BIASING FORCE ON EACH OF THE FIRST ENDS OF SAID MEMBERS; AND SECOND MEANS CONNECTING THE SECOND ENDS OF SAID FLEXIBLE MEMBERS TO SAID TABLE AND HAVING MANUALLY ENGAGEABLE MEMBERS FOR INDEPENDENTLY ADJUSTING THE EFFECTIVE LENGTH OF EACH OF SAID FLEXIBLE MEMBERS FOR ADJUSTING THE ALIGNMENT OF SAID STRAIGHT EDGE WHEREIN: EACH OF SAID BIASING MEANS INCLUDES A HOUSING HAVING A THREADED BORE THEREIN OPENING TO ONE END, SAID MANUALLY ENGAGEABLE MEMBER BEING FORMED AND DIMENSIONED FOR THERADABLE RECEIPT IN SAID BORE AND BEING FORMED WITH AN INTERNAL BORE THERETHROUGH, A PISTON MEMBER FORMED AND DIMENSIONED FOR SLIDING RECEIPT IN SAID INTERNAL BORE, FORMED WITH A SPRING RETAINER AND ADAPTED FOR RECEIVING AN END OF FLEXIBLE MEMBER AND A SPRING MOUNTED BETWEEN SAID SPRING RETAINER AND SAID MANUALLY ENGAGEABLE MEMBER FOR ADJUSTABLE BIASING OF SAID FLEXIBLE MEMBERS. 